Vasa Vasorum in Saphenous Vein for CABG: A Review of Morphological Characteristics.

This short article discusses selected scanning electron microscope and transmission electron microscope features of vasa vasorum including pericytes and basement membrane of the human saphenous vein (SV) harvested with either conventional (CON) or no-touch (NT) technique for coronary artery bypass grafting. Scanning electron microscope data shows the general damage to vasa vasorum of CON-SV, while the transmission electron microscope data presents ultrastructural features of the vasa in more detail. Hence there are some features suggesting pericyte involvement in the contraction of vasa blood vessels, particularly in CON-SV. Other features associated with the vasa vasorum of both CON-SV and NT-SV preparations include thickened and/or multiplied layers of the basement membrane. In some cases, multiple layers of basement membrane embrace both pericyte and vasa microvessel making an impression of a "unit" made by basement membrane-pericyte-endothelium/microvessel. It can be speculated that this structural arrangement has an effect on the contractile and/or relaxing properties of the vessels involved. Endothelial colocalization of immunoreactive inducible nitric oxide synthase and endothelin-1 can be observed (with laser confocal microscope) in some of the vasa microvessels. It can be speculated that this phenomenon, particularly of the expression of inducible nitric oxide synthase, might be related to structurally changed vasa vessels, e.g., with expanded basement membrane. Fine physiological relationships between vasa vasorum endothelium, basement membrane, pericyte, and perivascular nerves have yet to be uncovered in the detail needed for better understanding of the cells'specific effects in SV preparations for coronary artery bypass grafting.

Arterial smooth muscle dynamics in development and repair.

Arterial vasculature distributes blood from early embryonic development and provides a nutrient highway to maintain tissue viability. Atherosclerosis, peripheral artery diseases, stroke and aortic aneurysm represent the most frequent causes of death and are all directly related to abnormalities in the function of arteries. Vascular intervention techniques have been established for the treatment of all of these pathologies, yet arterial surgery can itself lead to biological changes in which uncontrolled arterial wall cell proliferation leads to restricted blood flow. In this review we describe the intricate cellular composition of arteries, demonstrating how a variety of distinct cell types in the vascular walls regulate the function of arteries. We provide an overview of the developmental origin of arteries and perivascular cells and focus on cellular dynamics in arterial repair. We summarize the current knowledge of the molecular signaling pathways that regulate vascular smooth muscle differentiation in the embryo and in arterial injury response. Our review aims to highlight the similarities as well as differences between cellular and molecular mechanisms that control arterial development and repair.

Characterization of the vasa vasorum in the human great saphenous vein: a scanning electron microscopy and 3D-morphometry study using vascular corrosion casts.

The vasa vasorum (VV) of explanted segments of the human great saphenous vein (Vena saphena magna; HGSV), harvested during dissection for coronary bypass grafts or diseased vein segments from the "Salzburger Landesklinikum," were studied by scanning electron microscopy and three-dimensional morphometry of microvascular corrosion casts. The main objective of this study was to examine the VV's structural arrangement in order to find the most vital segments of the HGSV and in turn to improve the results of coronary bypass surgeries. The study presents a meticulous analysis of the whole microvascular system of the VV of the HGSV and its three-dimensional arrangement. It is one of the first studies yielding detailed quantitative data on geometry of the VV of the HGSV. A detailed insight into different vascular parameters such as vessel diameter, interbranching, intervascular distances, and branching angles at different levels of the VV's angioarchitecture and in different parts of the HGSV in health and disease is given. Further, the geometry of bifurcations was examined in order to compute the physiological optimality principles of this delicate vascular system based on its construction, maintenance, and function.

Vasa vasora in the tunica media of goat aorta / Vasa vasora en la túnica media de la aorta de cabra

This study aimed at describing the distribution of vasa vasora in the tunica media of various parts of goat aorta, since this influences the physico-mechanical properties and disease occurrence. Specimens were obtained from ascending, arch, each vertebral level of descending thoracic and various segments of abdominal aorta of sixteen healthy adult male domestic goats (Capra hircus). They were fixed in 10 percent formaldehyde solution, and routinely processed for paraffin embedding. Seven micron thick sections were stained with Mason's Trichrome stain. Vasa vasora are present in the tunica media of all the aortic segments. In the proximal segments, they co-localize with muscle islands found in the adventitial half. Their density declines caudally, but they are still present in the tunica media even in the abdominal aorta where the thickness is less than 0.5mm and elastic lamellae less than 29. Vasa vasora in the goat aortic tunica media penetrate into the luminal half and are present even in relatively thin segments. This extent, which may enhance vascular health, suggests that the goat aortic wall is very active, a feature probably related to auxillary pump function of the muscle islands in the aortic wall.

El objetivo de este estudio fue describir la distribución de vasa vasora en la túnica media de diversas partes de la aorta de cabra, ya que esto influye en las propiedades físicas y la aparición de enfermedades. Las muestras se obtuvieron de 16 cabras machos adultos sanos (Capra hircus) desde la porción ascendente del arco aórtico, segmentos torácicos descendentes y de la parte abdominal de la aorta. Las muestras se fijaron en solución de formol al 10 por ciento, y fueron sometidas a procesamiento de rutina para inclusión en parafina. Secciones de siete micras de grosor se tiñeron con reacción tricrómica de Masson. Vasa vasora están presentes en la túnica media de todos los segmentos de la aorta. En los segmentos proximales, que localizan con islas de músculo que se encuentra en la mitad de la adventicia. Su densidad disminuye en sentido caudal, pero aún están presentes en la túnica media, incluso en la parte abdominal de la aorta, donde el espesor es inferior a 0,5 mm y láminas elásticas menos de 29. Vasa vasora en la túnica media de la aorta de la cabra penetran en el medio luminal y están presentes incluso en segmentos relativamente delgados. Esta medida, que puede mejorar la salud vascular, sugiere que la pared aórtica de la cabra es muy activa, una característica probablemente relacionada con la función de la bomba auxiliar de las islas del músculo en la pared aórtica.

Architectonic arrangement of the vasa vasorum of the human great saphenous vein.

OBJECTIVE: The detailed spatial arrangement of the vasa vasorum (VV) of the human great saphenous vein (HGSV) was demonstrated in qualitative and quantitative terms. MATERIALS AND METHODS: Segments of the HGSV taken from cadavers 12-24 h post mortem and from patients undergoing aortocoronary bypassing were studied by light microscopy of India-ink-injected specimens and by scanning electron microscopy of vascular corrosion casts. RESULTS: Arterial feeders were found to approach the HGSV from nearby arteries every 15 mm forming a rich capillary network within the adventitia and the outer two thirds of the media in normal HGSV, while in HGSV with intimal hyperplasia capillary meshes extended into the inner layers of the media. Within the media, capillary meshes ran circularly. Postcapillary venules drained centrifugally towards the adventitial venous vessels which finally formed venous drainers running adjacent to the arterial feeders. Three-dimensional morphometry of vascular corrosion casts of VV revealed that diameters of (i) arterial VV ranged from 11.6 to 36.6 microm, (ii) capillary VV from 4.7 to 11.6 microm and (iii) venous VV ranged from 11.6 to 200.3 microm. CONCLUSIONS: The 3D network of VV suggests these layers are metabolically highly active and therefore require a continuous blood supply. We conclude, therefore, that the VV network must be preserved during in situ bypassing.

The absence of lymphatics in normal and atherosclerotic coronary arteries in man: a morphologic study.

It has been suggested by various investigators that the impairment of lymphatic drainage from the coronary arteries may play a role in predisposition to coronary atherosclerosis, the pathogenesis of which is certainly multifactorial. In our study, no lymphatic vessels were found in the walls of the coronary arteries (adventitia, media and intima) in 51 human hearts from patients ranging in ages from 3 months to 83 years with normal coronary arteries, coronary atherosclerosis, and cardiomyopathy. Visualized lymphatics were located solely in the periadventitial area, and these lymphatics were more irregular in hearts from older persons. With injection, histology, and electronmicroscopy methods we could not detect penetration of lymphatics into the wall of coronary trunks in normal as well atherosclerotic arteries. In all coronary arteries studied, and particularly in the atherosclerotic lesions, blood vasa vasorum could be visualized. In the atherosclerotic areas, vasa vasorum (angiogenesis) could be seen penetrating into the media and intima. Many of the thin-walled vasa vasorum could easily be mistaken for lymphatics. The absence of lymphatics draining the epicardial coronary arteries may be a predisposing factor to coronary atherosclerosis.

Prefabricated engineered skin flap using an arteriovenous vascular bundle as a vascular carrier in rabbits.

BACKGROUND: The authors previously described induction of spontaneous tissue generation by implanting a collagen matrix and a ligated pedicle (arteriovenous bundle) into a hollow porous chamber in vivo in the rabbit. They hypothesized that increased tissue volume could be obtained by the application of basic fibroblast growth factor (bFGF) and/or by increasing the chamber size and porosity. METHODS: In rabbits, a saphenous arteriovenous pedicle and a collagen sponge were inserted into a porous chamber in the groin. Small-volume pore chambers (experiment 1, n = 7) and larger-volume, wider pore chambers (experiment 2, n = 13) were compared, and each was compared with and without bFGF. An additional three flaps of experiment 2 with bFGF were skin grafted, microsurgically transplanted to the ear, and evaluated at 6 months for stability. RESULTS: All patent chambers grew tissue; chambers with bFGF were almost filled, and those without were only half-filled. Histomorphometric analysis confirmed a significant difference. The larger-volume, larger-pore chambers produced more than twice the volume of tissue as the smaller chambers did, and this was significant. Tissue volume in both the control and bFGF groups of experiment 2 was significantly greater than that in the respective groups of experiment 1. Histology, angiography, and scanning electron microscopy confirmed greater vascularity in the bFGF groups and demonstrated vascular connections penetrating the chamber pores linking with angiogenic sprouts, probably from the vasa vasorum of the pedicle, to contribute to new growth. Transplanted flaps survived and appeared normal 6 months later. CONCLUSIONS: Patent pedicles, bFGF, large pore size, and larger-volume chambers all seemed to contribute to increased tissue growth in this model. The tissue is stable long term.

Types of vascular wall as related to vasa vasorum in common tree shrew (Tupaia glis).

Blood vessels of the common tree shrew (Tupaia glis) were embedded in Araldite, sectioned at 0.5-1 microm thickness, and observed with light microscope (LM). It was found that the vascular wall could be classified into three categories: (1) those with proper vasa vasorum (PVV); (2) those with collaborative vasa vasorum in perimural tissues; (3) those without vasa vasorum. The PVV were located in the the tunica media, between the tunica media and the tunica adventitia, and in the tunica adventitia of the vascular wall. On studying the vascular casts with a scanning electron microscope (SEM), it was noted that what appeared to be vasa vasorum did not always conform to those found under the LM. Furthermore, the PVV seen in a particular blood vessel among different tree shrews were not always related to intraluminal partial pressure of oxygen, vascular size, and thickness of the wall. In contrast, the results of this study indicate that the activeness of the vascular wall in varying the amount of blood flow to certain organs is an important factor that is associated with the existence, density, and distribution of the vasa vasorum.

Differential effect of experimental hypertension and hypercholesterolemia on adventitial remodeling.

OBJECTIVE: Intima-media remodeling, as frequently assessed by changes in the external elastic lamina-to-lumen area (EELLA), is well-described in coronary artery disease in contrast to adventitial remodeling, especially in the early disease stage. METHOD AND RESULTS: Female domestic pigs were randomized to one of the following 12-week treatment groups: normal diet (N; n=6), high-cholesterol diet (HC; n=6), or renovascular hypertension (HT; n=4). Low-density lipoprotein (LDL) cholesterol serum concentration was higher in HC than in N and HT (395.5+/-106 versus 38.6+/-14 and 37.2+/-6.8 mg/dL; P<0.05 for both). Mean arterial pressure was higher in HT than in N and HC (141.3+/-21 versus 107.4+/-8.9 and 109.4+/-7.8 mm Hg; P<0.05 for both). EELLA ratio, as assessed by morphometry, was similar in N, HC, and HTN (1.03+/-0.32 versus 0.95+/-0.29 and 1.01+/-0.09; P<0.05 for both). Coronary vasa vasorum density, as assessed by 3-dimensional micro-computed tomography, was higher in HC than in N and HT (3.4+/-1.0 versus 1.9+/-0.3 and 2.0+/-1.2; P<0.05 for both). In contrast, immunostaining showed a higher collagen III content and the presence of adventitial myofibroblasts in HT compared with N and HC. CONCLUSIONS: The current study suggests that adventitial remodeling precedes intima and media remodeling of coronary arteries early after exposure to hypercholesterolemia and hypertension, with distinct qualitative differences between them. Intima-media remodeling is well-described in coronary artery disease in contrast to adventitial remodeling. Results of the current study on coronary arteries of pigs, randomized to 12 weeks of normal diet (N), hypercholesterolemic diet (HC), or renovascular hypertensive (HT), indicate that adventitial remodeling precedes intima-media remodeling early after risk factor exposure with distinct qualitative differences.

Molecular imaging of atherosclerotic plaques using a human antibody against the extra-domain B of fibronectin.

Current imaging modalities of human atherosclerosis, such as angiography, ultrasound, and computed tomography, visualize plaque morphology. However, methods that provide insight into plaque biology using molecular tools are still insufficient. The extra-domain B (ED-B) is inserted into the fibronectin molecule by alternative splicing during angiogenesis and tissue remodeling but is virtually undetectable in normal adult tissues. Angiogenesis and tissue repair are also hallmarks of advanced plaques. For imaging atherosclerotic plaques, the human antibody L19 (specific against ED-B) and a negative control antibody were labeled with radioiodine or infrared fluorophores and injected intravenously into atherosclerotic apolipoprotein E-null (ApoE-/-) or normal wild-type mice. Aortas isolated 4 hours, 24 hours, and 3 days after injection exhibited a selective and stable uptake of L19 when using radiographic or fluorescent imaging. L19 binding was confined to the plaques as assessed by fat staining. Comparisons between fat staining and autoradiographies 24 hours after 125I-labeled L19 revealed a significant correlation (r=0.89; P<0.0001). Minimal antibody uptake was observed in normal vessels from wild-type mice receiving the L19 antibody and in atherosclerotic vessels from ApoE-/- mice receiving the negative control antibody. Immunohistochemical studies revealed increased expression of ED-B not only in murine but also in human plaques, in which it was found predominantly around vasa vasorum and plaque matrix. In summary, we demonstrate selective targeting of atheromas in mice using the human antibody to the ED-B domain of fibronectin. Thus, our findings may set the stage for antibody-based molecular imaging of atherosclerotic plaques in the intact organism.

Three-dimensional arrangement of the vasa vasorum in explanted segments of the aged human great saphenous vein: scanning electron microscopy and three-dimensional morphometry of vascular corrosion casts.

The vasa vasorum of skeletonized and nonskeletonized segments of five human great saphenous veins (GSVs), harvested during coronary bypass grafting, were cannulated, rinsed, and injected (casted) with the polymerizing resin Mercox-Cl-2B. After removal of the dry vascular tissue, the casts were examined using scanning electron microscopy. Stereopaired images (tilt angle, 6 degrees ) were taken, imported into a 3D morphometry system, and the 3D architecture of the vasa vasorum (arterial and venous vasa as well as capillaries) was studied qualitatively and quantitatively in terms of vasa diameters, intervascular and interbranching distances, and branching angles. Diameters of parent (d(0)) and large (d(1)) and small (d(2)) daughter vessels of arterial and venous bifurcations served to calculate asymmetry ratios (alpha) and area ratios (beta). Additionally, deviations of bifurcations and branching angles from optimal branches were calculated for selected arterial vasa. The arrangement of the vasa vasorum closely followed the longitudinally oriented connective tissue fibers in the adventitia and the circularly arranged smooth muscle cell layers within the outer layers of the media. Venous vasa by far outnumbered arterial vasa. Vasa vasorum changed their course several times in acute angles and revealed numerous circular constrictions, kinks, and outpouchings. Due to their spatial arrangement, the vasa vasorum are prone to tolerate vessel wall distension generated by acute increases in blood pressure or stretching of the vessel without severe impact on vessel functions. Preliminary comparisons of data from the bifurcations of cast arterial vasa vasorum, with calculated optimal bifurcations, do not yet give clear insights into the optimality principle(s) governing the design of arterial vasa vasorum bifurcations of the human GSVs.

Hypothesis: a potential role for the vasa vasorum in the maintenance of vein graft patency.

Autologous saphenous vein is the most commonly used conduit for coronary artery bypass surgery with more than 50% grafts occluding within 10 years. In conventional preparation the vein undergoes considerable surgical trauma with damage to the outer layers during harvesting. Within these regions are situated the vasa vasorum and small vessels providing oxygen and nutrients to the vessel wall. Certain vasa vasorum terminate in the vessel lumen where it is suggested that they have a physiological role. Preservation of the vasa vasorum of saphenous veins used as bypass conduits may play an important role in the maintenance of graft patency.

The human testicular artery and the pampiniform plexus--where is the connection?

The aim of the study was the microscopic evaluation of the human spermatic cord vessels, with special attention to the connection between the testicular artery and the veins of the pampiniform plexus. We used the corrosive cast method to visualise the angioarchitecture of the spermatic cord. Casts were evaluated using a scanning electron microscope. We observed that there is a narrow space (previously filled with the testicular artery wall), between the casts of the testicular artery and the veins of the pampiniform plexus. This area contains a capillary vessel net, which connects the testicular artery with the veins of the pampiniform plexus. There were no direct anastomoses between the testicular artery and the pampiniform plexus. We hypothesise that the capillary net described is the means of connection between the testicular artery and the pampiniform plexus, and that there can be a testicular artery net of its own vessels (vasa vasorum).

Effect of impaired vasa vasorum flow on the structure and mechanics of the thoracic aorta: implications for the pathogenesis of aortic dissection.

OBJECTIVE: To investigate the alterations of structure and mechanical properties of the aortic wall, resulting from impairment of vasa vasorum flow. METHODS: Eight healthy Landrace pigs were subjected to interruption of vasa vasorum flow to the upper segment of their descending thoracic aorta. Under sterile conditions, the periaortic tissue was excised and the contiguous intercostal arteries were ligated. Ten sham-operated pigs were used as controls. Fifteen days postoperatively, the animals were sacrificed and their upper descending thoracic aortas were removed. Histology, and collagen and elastin content determination by image analysis technique were performed. Mechanical analysis of aortic strips was carried out with a uniaxial tension device and stress-strain curves were obtained. RESULTS: In contrast to normal aortic walls of the control group, histology of the avascular aortas revealed severe ischemic necrosis of the outer media along with abnormal straightening of the elastin and collagen fibers, without significant collagen and elastin content changes. The borderline between the outer ischemic and inner non-ischemic media was sharp, and an outset of dissection was observed at this point. Mechanical analysis showed that at the same level of strain, the ischemic aorta was significantly stiffer at both low (P=0.03) and high strains (P=0. 003). CONCLUSIONS: Impairment of blood supply to the thoracic aorta leads to abnormal morphology of elastin and collagen fibers of the outer media, resulting in increased aortic stiffness under a wide range of stresses. In the clinical setting, decreased vasa vasorum flow, reportedly occurring in arterial hypertension, may increase the stiffness of the outer media of the thoracic aorta and produce interlaminar shear stresses, contributing to the development of aortic dissection.

Vasa vasorum of blood and lymph vessels in the broad ligament of the sheep uterus analyzed by scanning electron microscopy.

The morphology of vasa vasorum of the blood and lymph vessels in the broad ligament of the uterus was examined in 12 adult ewes. The technique of vascular corrosion casts with the usage of Mercox resin allows multiple surveys of a three-dimensional organization of vascular networks under a scanning electron microscope (SEM). The study was appended by tissue pieces dried by the critical point method for SEM and semi-thin sections stained with toluidyne blue for light microscopy. Vasa vasorum surrounded both the larger vessels and the lymph vessels emanating from the ovary and the uterus. Significant differences in location and intensity of vasa vasorum in blood vessels were observed. They were less developed in the first part of the ovarian and the uterine arteries than in their smaller branches. Significantly large, two- or even three-layer vasa vasorum surrounded the ovarian and the uterine branches of the ovarian artery as well as the ovarian veins in the area of mesovarium. In the other areas of the broad ligament of the uterus, arterial vessels of similar sizes usually had a single-layer vasa vasorum. The lymph vessels leaving the ovary and uterus were surrounded by dense, although usually single-layed, microvascular network. The presence of vasa vasorum on relatively small blood and lymph vessels of the broad ligament of uterus indicates their particular functions that are probably connected with the estrous cycle or pregnancy and changes of blood flow rate entering the ovary and uterus. However, the presence of significantly developed, multi-layer vasa vasorum networks on only some of the blood vessels indicates that it is probably one of the vessels morphological adaptations to serve the counter-current transfer of biologically-active regulators in the area of the broad ligament of the sheep's uterus.

Three-dimensional structure of the bronchial microcirculation in sheep.

BACKGROUND: The bronchial circulation affects both pulmonary vascular and airway activity. Fundamental to understanding the role of the bronchial microcirculation in health and disease is understanding its anatomy. This study sought to identify specific structural elements that might contribute to the drop that occurs between the systemic blood pressure of the bronchial artery and the low pressure of the pulmonary bed into which the bronchial circulation flows and to better describe the connections of the bronchial and pulmonary circulations. METHODS: To do this, the lungs of five sheep were cast by injecting a resin through bronchial and pulmonary arteries. After taking samples for light microscopy, the tissue was digested and the casts were viewed with a scanning electron microscope. RESULTS: Casts of extrapulmonary bronchial arteries were structurally similar to other systemic arteries. Tortuous ones spiraled around bronchi and large blood vessels. Intrapulmonary bronchial arteries, about 100-300 microns in diameter, had sharp branching and deep focal constrictions with great rugosity that completely shut off the flow of the resin. These vessels correspond to the Sperrarterien described by von Hayek (and could cause the resistance associated with the pressure drop). Vasa vasorum ran in the walls of intrapulmonary pulmonary arteries for a variable distance before they entered the lumens of the pulmonary arteries. The smallest blood vessel found that was supplied with vasa vasorum was a bronchial artery 42 microns in diameter. Capillary-like networks with large luminal diameters were found on the pleural surface. CONCLUSIONS: Scanning electron microscopy of microvascular casts provides a fresh description of the bronchial circulation, further delineates the communications of these two circulations, and may structurally account for some pressure drop between the bronchial and pulmonary circulations.

Age-related alterations in the morphology of femoral artery vasa vasorum in the rat.

The objective of this study was to explore any age-related morphological changes in the vasa vasorum of the rat femoral artery. Vascular corrosion casts were prepared from 2, 12 and 24-month-old rats. Examination of the casts with the scanning electron microscope revealed dramatic differences in the appearance of the vessels of young and aged rats. The vasa vasorum of 2-month-old rats consisted of a dense network of capillaries. These vessels were dramatically reduced in number by 12 months, and even fewer capillaries were present at 24 months. This reduction in capillary density is consistent with the observed age-related decreases in oxygen tension and may explain why the aged are more prone to atherosclerosis.

The vasa vasorum of the rabbit carotid artery.

The anatomy of the vasa vasorum of the carotid arteries was assessed by light and electron microscopy in a series of 25 New Zealand White male rabbits. The low viscosity acrylic resin, LR White, was used to cast the microvasculature. The carotid artery was found to have an endothelial monolayer placed directly upon a broad fenestrated internal elastic lamina. The media consisted of 12-18 laminae comprised of smooth muscle cells, elastin, collagen and ground substance. Vasa vasorum were confined to the adventitial layer, with no penetration into the media. They arose directly from the lumen of the carotid artery in addition to the arterial branching points. The potential role of the vasa vasorum in the aetiology of atherosclerotic plaques is discussed.

Histological framework of lymphatic vasa vasorum of major arteries: an experimental study.

We investigated the histological framework of lymphatic vasa vasorum of major arteries in the rabbit and guinea pig combining the "natural filling method" with light and transmission electron microscopy. An absorbing adventitial lymphatic network consisting of large and sparsely distributed vessels with capillary structure occupied a more external arterial wall position than blood capillaries. The latter were smaller, more numerous, densely distributed, and located closer to the arterial lumen at the media-adventitial border. Periarterial lymphatics (with the structure of absorbing lymph vessels) encircled the wall of the major arteries and formed a rich and irregular plexus. The topography and anatomic structure of these absorbing lymph vessels suggest that lymphatic drainage plays a significant role in large arterial wall homeostasis.

[Scanning electron microscopy analysis of peroperative injury at the junctions of the vasa vasorum and the collateral veins of venous autografts prepared for myocardial revascularization]. / Scann-elektronskomikroskopska analiza peroperativnih ostecenja utoka vasa vasorum i kolateralnih vena venoznog autotransplantata pripremljenog za revaskularizaciju miokarda.

The authors' objective was to determine the peroperative changes in affluences of collateral veins and vasa vasorum of venous autografts prepared for a coronary bypass by standard and proposed methods. The investigations were carried out on dogs. In control group, the veins were prepared by the standard method where the vein is presented by several minor incisions with "skin bridges" planted in between. In the second group, the veins were prepared by the method developed by the authors, where the vein is presented by a long incision, maintaining perfusion with its own blood throughout surgery. The scanning electron microscope analysis has shown that the standard method of vein preparation causes significant damage in collateral veins and vasa vasorum affluences which are actually part of an internal surface of future venous autograft prepared for myocardium revascularization. The proposed surgical method considerably reduces possible peroperative damage of the vasa vasorum and collateral vein affluence sites forming a portion of the internal surface of the venous autograft. Therefore, based on the obtained results, this method is recommended for clinical application.